The present invention relates to an ultrasonic nebulizer, and more particularly to such an ultrasonic nebulizer, which is practical for use in an inhaler, a humidifier, as well as a mist maker.
A regular ultrasonic nebulizer for use in an inhaler, humidifier or mist maker, is generally comprised of an ultrasonic vibrator controlled to produce sound field for making water or medicine into a mist. The sound field includes a far field area and a near field area. The border area between the far field area and the near field area is the sound wave energy concentrated area. However, because the sound wave is dispersed radially, it is not easy to effectively control the concentrated sound wave energy to break through the surface of the liquid. Improper control of the sound wave energy cannot evenly nebulize the liquid. U.S. Pat. No. 3,901,443 teaches a method of changing the sound wave emitting angle of an ultrasonic vibrator. According to U.S. Pat. No. 3,901,443, the sound wave emitting angle is set between 2.degree.-22.degree.. However, this method has its application limitation. For example, this method cannot eliminate refraction of sound waves in space, medicine cup, or partition means.